Now that I'm at the end of it all, I can say that Sins of a Solar Empire felt a lot better to me than the last 4X/RTS hybrid I played, StarDrive. I think it's because Sins doesn't really let you fall into any serious infrastructure traps. There's a slight credit penalty for new, underdeveloped planets, but it's trivial to work past and you still get the system's full portion of minerals and crystals. So you're never in a situation where expanding to a new planet hurt you. And unlike, say Galactic Civilizations II, the map is small enough that expansion never really felt like a grind. Each individual planet was valuable enough to mount a campaign over.
Which speaks well to the game's balance. I'm not usually a big RTS guy, but I did find myself becoming invested in my war of interplanetary conquest. Or, at least, I did once I realized the AI would stab me in the back at the first sign of weakness and thus I had to over-fortify my border planets with a full complement of defensive starbases to compensate for my under-developed fleet. The way fleets work in this game, you pay a maintenance penalty based on the maximum size of your fleet, regardless of how many ships you have, and thus I had the idea that it would be best to research new fleet size technologies last so as to delay the penalty as long as possible. This led to me being slammed by pirates and/or ambitious neighbors more times than I care to admit. And now that I think about it, building all those Gauss cannons and defense hangars probably ate up more resources than I saved with the lower maintenance costs . . .
Whatever. Like I wasn't going to build everything at every planet anyway. As of my last game, my strategy was working, and that's all that matters. I may have my doubts about RTS games, but winning goes a long way towards soothing those doubts away.
To sum up, I went into this game with a smidgen of diffidence, and I'm coming out of it only slightly ambivalent. There were frustrating parts, but I could clearly see how my actions connected to the outcome and subsequently improve my performance. I didn't like that there was so much unrestrained warfare, but once I figured out how to keep myself safe, there was plenty still left to do. All in all, I'm looking forward to Sins of a Solar Empire: Rebellion more than I was before, so in that sense Trinity was a success.